JPH03175230A - Operation controller of air conditioner - Google Patents

Abstract

PURPOSE:To smoothly start a cooling operation even in a low outside air temperature by setting the initial openings of utilizing side expansion valves larger than an overheating degree control opening, reducing the air capacity of the fan of a heat source side heat exchanger and, on the other hand, opening all the utilizing side expansion valves only in starting. CONSTITUTION:A refrigerant discharged from a compressor 1 is condensed in an outdoor heat exchanger 4 and shunted to indoor units A and B wherein the pressure of the refrigerant is reduced by indoor motor-operated expansion valves 7 and 7. After evaporated by indoor heat exchangers 8 and 8, the shunted refrigerants join together again and return to the compressor 1. In a cooling operation described above, capacity control means 51 open and close a valve 18 based on an indoor temperature detected by a room temperature thermometer Th3 and the capacity of the compressor 1 is controlled to a full load or an unloading. The openings of the indoor motor- operated expansion valves 7 are overheat-degree-controlled by opening control means 53 based on the detected temperatures of an indoor liquid pipe sensor Th4 and an indoor gas pipe sensor Th5 and, on the other hand, the air capacity of an outdoor fan 12 is controlled to a low air capacity L or to a high air capacity by air capacity control means 54 based on the outdoor air temperature detected by an outdoor air temperature sensor Th1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an operation control device for an air conditioner equipped with a use-side expansion valve whose opening degree can be freely adjusted, and in particular relates to a start-up countermeasure for cooling when the outside air temperature is low. It is something.

(Prior art) Conventionally, air conditioners have been equipped with, for example,
As disclosed in Publication No. 7541, a compressor whose operating capacity can be adjusted in two stages of full load and unload by an unloader mechanism, an outdoor heat exchanger equipped with an outdoor fan, and an outdoor expansion valve; Some devices have an indoor expansion valve and an indoor heat exchanger connected in sequence. and,
During cooling operation, the compressor is divided into three steps based on the temperature difference between the indoor temperature and the set temperature, and the operating capacity of the compressor is adjusted according to the indoor air conditioning condition, and the capacity is adjusted for the cooling load to achieve the specified level. It is designed to have a cooling effect.

(Problems to be Solved by the Invention) The above-mentioned air conditioner may perform cooling throughout the year, such as air conditioning in a computer room, and may perform cooling operation even when the outside air temperature is low, such as in winter. In this low outside air condition, when starting cooling operation, the operating capacity of the compressor is set to the unload state, but since the indoor electric valve is set to control the degree of superheat, the initial opening at startup is Once throttled, the pressure becomes low (pressure on the suction side of the compressor)
There was a problem that the In particular, when the outdoor fan operates, the high pressure (condensing pressure) decreases, the difference between high and low pressures becomes small, the amount of refrigerant circulating decreases, the low pressure decreases, a low pressure cut occurs, and the cooling operation stops. was there.

The present invention has been made in view of the above, and an object of the present invention is to smoothly start the cooling operation even when the outside air temperature is low.

(Means for Solving the Problems) In order to achieve the above object, the means taken by the present invention is to set the initial opening degree of the utilization side expansion valve to be larger than the superheat degree control opening degree, and in addition to this, to While reducing the fan air volume of the side heat exchanger, all the usage-side expansion valves are opened only at startup.

Specifically, as shown in FIG. 1(a), the measures taken by the invention according to claim (1) first include a variable capacity compressor (
1), a heat source side heat exchanger (4), a user side expansion valve (7) whose opening degree can be freely adjusted, and a user side heat exchanger (8) are connected in this order. There is.

The capacity control means (51) adjusts the capacity of the compressor (1) according to the air conditioning load, and the utilization side expansion valve (7).
) is provided with an opening degree control means (53) for controlling the opening degree of the opening according to the degree of superheating so that the degree of superheating is constant, and a temperature detection means (Th1) for detecting the outside air temperature and outputting a temperature signal. It is being Furthermore, the temperature detection means (
When the outside air temperature drops below a preset temperature in response to the temperature signal Th1), the compressor (1) is operated instead of controlling the capacity control means (51) within a predetermined time from the time of startup. A starting capacitance means (55) is provided that outputs a capacitance signal to forcibly drive with a low capacitance. In addition, the temperature detection means (Th1)
If the outside air temperature drops below a preset temperature in response to a temperature signal from The configuration includes a starting opening means (56) that outputs an opening signal so that the starting opening is forcibly set to a starting opening that is a predetermined opening larger than the superheat degree control opening.

Furthermore, the means taken by the invention according to claim (2) is that, in the invention according to claim (1), an air volume control means (54) for adjusting the air volume of the fan (12) is provided, while starting the cooling operation. If the outside air temperature drops below a preset temperature in response to a temperature signal from the temperature detection means (Th1), the air volume control means (Th1) is activated within a predetermined time from the time of startup.
In place of the control in step 4), a starting air volume means (57) is provided for outputting an air volume signal to forcibly stop or drive the fan (12) at a low air volume.

Moreover, as shown in FIG. 1(b), the means taken by the invention according to claim (3) is that the compressor (1), the heat source side heat exchanger (4), and the Multiple user-side expansion valves (7)
, (7), ... and multiple user-side heat exchangers (8)
, (8),... are assumed to be connected to each other, and each of the user-side expansion valves (7), (7),...
・Each user side heat exchanger (8).

When the heat exchange operations of (8), . . . 7), (7)
an opening control means (53) for controlling the opening degree of . . . so that the degree of superheating is constant according to the degree of superheating; A detection means (Thl, PL) is provided. Then, upon starting the cooling operation by at least one of the user-side heat exchangers (8), an outside air temperature or a saturation temperature equivalent to evaporation pressure is set in advance in response to a temperature signal from the temperature detection means (Thl, PI). If the temperature has dropped below the temperature, the opening control means (53) will control all the user-side expansion valves (7), (7), etc. within a predetermined time from startup to the predetermined startup opening. The configuration includes a starting opening degree means (58) that outputs an opening degree signal to set the opening degree.

(Function) With the above configuration, in the invention according to claim (1), during cooling operation, the capacity control means (51) adjusts the capacity of the compressor (1) according to the cooling load, while the opening control means ( 5
3) controls the supermaturity of the user-side expansion valve (7) and controls the cooling operation.

At the time of starting this cooling operation, the temperature detection means (Th1
) detects an outside temperature lower than a preset temperature, the starting capacity means (55) outputs a capacity signal, and the starting opening degree means (56) outputs an opening degree. Then, the compressor (1) is set to a low capacity, and the user-side expansion valve (7) is set to an opening larger than the superheat degree control opening, and cooling operation is started. As a result, even if the outside air temperature is low at startup, a predetermined amount of refrigerant circulation is ensured, and the low pressure (pressure on the suction side of the compressor (1)) is maintained above a predetermined value, allowing cooling operation. is carried out smoothly.

Further, in the invention according to claim (2), the air volume control means (5
4) controls the fan (12) on the heat source side, and when the outside air temperature is lower than a predetermined temperature at the time of starting the cooling operation, the starting air volume means (57) outputs an air volume signal. In addition to starting control of the compressor (1) and the usage-side expansion valve (7),
The air volume of the fan (12) is reduced, for example, stopped or controlled to a low air volume. This allows the heat source side heat exchanger (
4) The amount of heat exchange is reduced, the high pressure (condensation pressure) is maintained at a predetermined value, and the low pressure is more reliably maintained at a predetermined value.

Further, in the invention according to claim (3), the plurality of user-side heat exchangers (8), (8) are used from the time of stopping the cooling operation.

When the cooling operation, that is, the heat exchange operation, of at least one of the utilization-side heat exchangers (8) is started, all the utilization-side expansion valves (7) are activated when the outside air temperature is low.

(7), .

(Effects of the Invention) Therefore, according to the invention according to claim (1), when the outside air temperature is low at the time of starting the cooling operation, the capacity of the compressor (1) is reduced and the usage side expansion valve (7 ) by increasing the opening degree, a predetermined amount of refrigerant circulation can be ensured, and a drop in low pressure can be prevented. As a result, even if the outside air temperature is low, low pressure cut does not occur, and cooling operation can be started smoothly, so that comfortable cooling can be reliably performed.

Further, according to the invention according to claim 2, when the outside air temperature is low, the fan (12) is stopped or the air volume is reduced, so that a drop in high pressure can be prevented. Since the accompanying low pressure drop can be prevented, cooling operation can be started more reliably, and comfort can be further improved.

Further, according to the invention according to claim (3), since the plurality of user-side expansion valves (7), (7), etc. are all opened at the time of startup at low outside air temperature, the refrigerant circulation amount is controlled to a predetermined level. Since the value can be maintained reliably, a drop in low pressure can be reliably prevented. In particular, even when the piping length is long or only the user-side heat exchanger (8) with a small capacity is operated, a predetermined amount of refrigerant circulation can be reliably ensured, making it possible to prevent low pressure cuts. A smooth start of cooling operation can be ensured.

(Example) Examples of the present invention will be described below with reference to FIGS. 2 to 6.

FIG. 2 shows a refrigerant piping system of an air conditioner according to an embodiment of the present invention, in which two indoor units (A) and (B) are connected in parallel to one outdoor unit (X). It is a multi-type product.

In the above outdoor unit (X), (1) is a compressor, (
2) is a demister that collects oil in the discharged refrigerant, (3) is a four-way switching valve that switches as shown in the solid line in the figure during cooling operation, and as shown in the broken line in the figure during heating operation, and (4) is an outdoor fan ( 12), an outdoor heat exchanger which is a heat source side heat exchanger that functions as a condenser during cooling operation and as an evaporator during heating operation; (4a) is the outdoor heat exchanger (4);
(5) is an outdoor electric expansion valve that adjusts the refrigerant flow rate during cooling operation and reduces the pressure of the refrigerant during heating operation;
(6) is a receiver for storing liquid refrigerant, and (9) is an accumulator for removing liquid refrigerant from the suction refrigerant.

In addition, the above-mentioned indoor units (A) and (B) have the same configuration, and both have an indoor electric expansion valve as a user-side electric expansion valve that reduces the pressure of the refrigerant during cooling operation and adjusts the refrigerant flow rate during heating operation. Expansion valve (7) and indoor fan (13)
) 2. The indoor heat exchanger (8), which is a user-side heat exchanger, functions as an evaporator during cooling operation and as a condenser during heating operation, as main equipment.

Each of the above devices (1) to (9) is connected to a refrigerant pipe (10).
A main refrigerant circuit (11) is configured, which is connected to allow the flow of refrigerant and transfers heat (or cold heat) obtained through heat exchange with outdoor air and imparts it to indoor air. The outdoor fan (12) in the outdoor unit (X) is configured to be able to switch the air volume between high air volume ff1H and low air volume.

Although not shown, the compressor (1) includes a scroll mechanism that discharges the sucked refrigerant at high pressure by the relative revolution of two opposing scrolls, and a fixed scroll in the middle of the scroll mechanism. It has a built-in unloader mechanism with a bypass hole that bypasses a portion of the discharged refrigerant.

A capillary tube 06 is connected from the discharge pipe (1, Oa) to the back pressure side of the unloader piston of the unloader mechanism.
), and an unloader passage (17) that connects the middle of the high pressure supply passage (15) and the suction pipe (10b) via an on-off valve (18).
When the on-off valve (18) is closed, high pressure is supplied to the unloader mechanism to bring the operating capacity of the compressor (1) to 100% full load.
8) is opened, low pressure is supplied to the unloader mechanism so that the operating capacity of the compressor (1) becomes unloaded, which is 50% of the full load.

Furthermore, many sensors are arranged in this air conditioner, (Thd) is a discharge pipe sensor arranged in the discharge pipe (10a) and detects the discharge pipe temperature, and (Th1) is the outdoor heat exchanger (10a). The outside temperature sensor (Th2) is placed at the air suction port of 4) and is a temperature detection means for detecting the intake air temperature TO as the outside air temperature, and is placed on the liquid pipe side of the outdoor heat exchanger (4). The outdoor liquid pipe sensor (Th3) that detects the liquid pipe temperature of the heat exchanger (4) is placed at the air suction port of the indoor heat exchanger (8), and detects the indoor air temperature and the suction air temperature Ta. The room temperature thermometer to detect, (Th4) is placed in the liquid pipe of the indoor heat exchanger (8), and the indoor liquid pipe sensor that detects the liquid pipe temperature Te of the indoor heat exchanger (8), (Th5) is the indoor heat exchanger The indoor heat exchanger (8) is placed in the gas pipe of the
) Indoor gas pipe sensor that detects the gas pipe temperature of (Hps
) is placed in the discharge pipe (10a) and stops the compressor (1) when the high pressure rises too much! High-pressure pressure switch, (L
1) S) is placed in the suction pipe (10b) and is a low pressure switch to stop the compressor (1) when the low pressure drops excessively; During operation, the refrigerant pressure is low (evaporation pressure equivalent saturation temperature Te)
During heating operation, high pressure (condensing pressure equivalent saturation temperature Tc)
A pressure sensor (Ps) is disposed in the discharge pipe (10a) and opens the on-off valve (18) before the discharge pressure reaches an excessively high value at which the high pressure switch (Hps) operates. This is a pressure switch for maintaining the compressor (1) in an unloaded state and switching the outdoor fan (12) from high air volume H to low air volume during heating operation, and from low air volume ff1L to high air volume H during cooling operation. Each of the above-mentioned sensors is connected to a controller (50), and the operation of the air conditioner is controlled according to the signals from each sensor.

In the figure, (19) indicates the demister (2) and the compressor (
1) is connected to the suction pipe (10b) via a capillary (20) to return oil, and (21) is a connecting pipe between the outdoor unit (A) and the indoor side. It is a closing valve installed inside.

The controller (50) includes a capacity control means (51) of the compressor (1) and a first opening r of the outdoor electric expansion valve (5).
#U control means (52), second opening degree control means (53) for the indoor electric expansion valve (7), and air volume control means (54) for the outdoor fan (12) are configured. The capacity control means (51) opens and closes the on-off valve (18) based on the room temperature detected by the room temperature thermometer (Th3) and the empty load to fully load and unload the capacity of the compressor (1). and is configured to control. The first opening degree control means (52) controls the degree of superheating of the outdoor electric expansion valve (5) based on the temperature detected based on the outdoor liquid pipe sensor (Th2) and the pressure sensor (P1) during heating operation. On the other hand, the second opening control means is used during cooling operation, that is, when the indoor heat exchanger (8)
(8) During the heat exchange operation, the indoor electric expansion valve (7) is activated for each indoor unit (A), (, B) depending on the temperature detected by the indoor liquid pipe sensor (Th4) and the indoor gas pipe sensor (Th5).
is controlled so that the degree of superheat is constant according to the degree of superheat, and the operation of each indoor unit (A) and (B) is stopped2.
When the thermostat is turned off and the thermostat is turned off, that is, the indoor heat exchanger (8).

(8) When the heat exchange operation is stopped, the indoor unit (A),
The indoor electric expansion valves (7) and (7) in (B) are controlled to be fully closed. The air volume control means (54) is configured to control the air volume of the outdoor fan (12) based on the temperature detected by the outside temperature sensor (Th1).

The controller (50) also includes a starting capacity means (
55), starting opening means (56), and starting air volume means (57)
and a compressor (1) when the outside air temperature is low during cooling operation.

It is configured to control an indoor electric expansion valve (7) and an outdoor fan (12). The starting capacity means (55) outputs a capacity signal when the outside air temperature is below 24°C, and by unloading (low capacity) the compressor (1) is forcibly increased to 30°C from the time of starting.
It is configured to run for seconds. The starting opening degree means (56) outputs an opening signal so that the opening degree is greater than the superheat degree control opening degree, and when the outside air temperature is below 18°C, the first starting opening degree is set to be higher than 18°C. When the brightness is high, the second activation brightness is forcibly maintained for 3081 hours from the time of activation. Further, the startup air volume means (57) outputs an air volume signal, and when the outside air temperature is 6°C or less, the outdoor fan (12) outputs an air volume signal.
) is stopped, and the wind is forced to low wind fikL when it is below 13°C, and to high wind fiH when it is higher than 13°C.

Next, the cooling operation of the air conditioner will be explained.

First, the refrigerant discharged from the compressor (1) is passed through the outdoor heat exchanger (
4) and condense in each indoor unit) (A).

(B), is depressurized by indoor electric expansion valves (7), (7), is evaporated in each indoor heat exchanger (8), (8), and then merges and returns to compressor (1). become.

During this cooling operation, the capacity control means (51) opens and closes the on-off valve (18) based on the indoor temperature detected by the room temperature thermometer (Th3), and the capacity of the compressor (1) is set to full load or unload. controlled. Further, the opening degree of the indoor electric expansion valve (7) is controlled by the degree of superheating (degree of superheating 5 ℃), while the air volume of the outdoor fan (12) is determined by the outside temperature sensor (Th
1) based on the outside air temperature detected by the air volume control means (54).
), the air volume is controlled to low or high.

Next, the startup control during the cooling operation will be explained based on the control state diagram in FIG. 3 and the control flow diagrams in FIGS. 4 to 6.

In addition, the outdoor electric expansion valve (
5) is set to a fully closed state (especially when the outside air is low).

Therefore, first, the compressor (1) starts, and in step STI it is determined whether or not it is in cooling operation. If it is set to heating operation, the process moves to step ST2, normal heating operation control is performed, and the process returns. On the other hand, if the cooling operation is set, the process moves from step STI to step ST3, and it is determined whether or not the air conditioner is in operation. If the operation is not in progress, that is, if the operation switch has not been turned on, the process moves to step ST4 and returns to the normal stop state, whereas if the operation switch is turned on and the operation is in progress, the process proceeds from step ST3. Proceeding to step ST5, it is determined whether or not the timer TMI is counting.

In this step ST5, if the timer TMI is counting, the process moves to step ST6, and it is determined whether or not it is started. If the operation switch is turned on, it is determined that the timer TMI is started, and the process moves to step ST7, and the timer TMI, TMl (3
A 0 second timer) is set and the process moves to step ST8, where it is determined whether the outside air temperature To is 20°C or higher. and,
If this outside air temperature To is lower than 20°C, step S
Moving from T8 to step ST9, the compressor (1) is started at a low capacity for unloading, while the outside air temperature TO is 2.
If the temperature is higher than 0°C, step ST8 to step 5T.
Moving to IO, the compressor (1) is set to a capacity corresponding to the indoor load, for example, the indoor temperature, and is started with unload or full load. In other words, when the outside air temperature To is below 20°C (see PI in Figure 3), the starting capacity means (55) outputs a capacity signal, opens the on-off valve (18), and forcibly unenergizes the compressor (1). While it starts and returns with a low load capacity, if the outdoor temperature To is higher than 20℃, the indoor thermostat (Th
The on-off valve (18) is opened and closed based on the detected temperature in step 3), the compressor (1) is started with unload or full load, and the process returns.

Thereafter, the operations from step STI are repeated, and in step ST5, since the timer TMI has started counting (see step ST7), steps ST6 and Sr1 are skipped, the process moves to step ST8, and the above-mentioned operations are repeated. Become. That is, when the outside air temperature To is 20° C. or lower, the compressor (1) is started with unloading regardless of the indoor load, and the compressor (1) is driven with this unloading for 30 seconds.

After that, the timer TM set in step ST7 above
When I times up, the process moves from step ST5 to step ST6, and since it is currently being driven, step S
The process moves from T6 to step 5T11, where normal cooling operation is performed and the capacity of the compressor (1) is controlled based on the indoor load and the like.

Further, as shown at points 21 and 22 in FIG. 3, the capacity of the compressor (1) at startup may be set in consideration of the outside air temperature To at the time of shutdown before startup. In other words, if the outside air temperature To at the time of shutdown is 20°C or less, if the outside air temperature TO is 24°C or less at startup, the compressor (1) will be started with forced unloading, and Outside temperature T
If o is higher than 20° C., the capacity of the compressor (1) is set according to the outside air temperature To at the time of startup as in the flow described above.

Next, the control of the indoor electric expansion valve (7) will be explained based on FIG. 5. In steps 5T21 to 5T27, steps STI to S in the flow of the compressor (1)
Similar to T7, when heating operation is set, the process moves from step 5T21 to step 5T22, and normal heating operation is started.
jtj control is performed and the cooling operation is stopped at step 5T.
The process moves from step 23 to step 5T24, and is controlled to a fully closed state. Then, when the cooling operation starts, step 5T25
The judgment is N because timer TMI is not currently set.
o, and the determination in step 5T26 is YES since it is currently activated, and in step 5T27 the timer T is
MI is set.

After that, the process moves to step 5T28, and the outside air temperature TO is 15
It is determined whether or not the temperature is above ℃, and the outside air temperature T is determined.

If it is lower than 15° C., the process moves from step 5T28 to step 5T29, sets the initial opening AT to the first starting opening shown in the following equation, and returns.

AT-40X (Ta+30) +++ ■Ta: Indoor temperature (temperature detected by indoor thermometer (T h 3)) On the other hand, if the outside temperature To is higher than 15°C, the process moves from step 5T28 to step 5T30, and the initial opening AT is changed. Set the second starting opening degree shown in the following formula and return.

AT-40XTa ---■ In other words, when the outside temperature To is lower than 15℃ (Fig. 3E
1), the starting opening degree means (56) outputs an opening degree signal,
Set the indoor electric expansion valve (7) to a position larger than the superheat degree control opening.
While setting the initial opening AT of the equation, the outside temperature To is 15
If the temperature is above ℃, the indoor electric expansion valve (7) is set to the initial opening AT of formula (2) to increase the refrigerant flow rate.

After that, the operation from step 5T21 is performed, and thereafter steps 5T26 and 5T27 are skipped and the above-mentioned operation is performed, and the indoor electric expansion valve (7) is forced to maintain the predetermined initial interval AT until 30flJ+ has elapsed from the time of startup. is set to

When the timer TMI times up after the above 30 seconds have elapsed, the process moves from step 5T26 to step 5T31, and the indoor electric expansion valve (7) is controlled by normal superheat degree control (SH
-5℃) and return.

In addition, as shown at point 61 and point E2 in Figure 3, in the same way as the control of the compressor (1), the outside air temperature To at the time of shutdown is considered, and when the outside air temperature To at the time of shutdown is 15 degrees Celsius or less, When the outside air temperature To at startup is 18°C or less, the indoor electric expansion valve (7) is set to the initial opening AT of the 0th formula, and when the outside air temperature To at the time of stop is higher than 15°C, the above-mentioned The indoor electric expansion valve (7) may be controlled as shown in the flow below.

Next, the control of the outdoor fan (12) will be explained based on FIG. 6. In steps 5T41 to 5T47, steps STI to
Similar to ST7, when heating operation is set, the process moves from step 5T41 to step 5T42, where normal heating operation control is performed, and when cooling operation is stopped, step 5T
43 to step 5T44, outdoor fan (12)
Control the stop. Then, when the cooling operation starts, the determination in step 5T45 is NO because the timer TMI is not currently set, and the determination in step 5T46 is YES since it is currently started, and the determination in step 5T4 is YES.
At 7, timer TMI is set.

After that, the process moves to step 5T48, and the outside air temperature TO is 11.
(See Figure 3 F1) to determine whether it is lower than 11°C.
If it is lower, the process moves to step 5T49 and the outside air temperature T
Determine whether o is lower than 4°C (see Figure 3 F2)
. Then, if the outside air temperature To is lower than 4°C, the process moves from step 5T49 to restep 5T50, and the outdoor fan (
12) is stopped and returned, while the outside temperature To is 4.
If the temperature is higher than ℃, step 5T is performed from step 5T49.
51, the outdoor fan (12) is set to a low air volume, and the process returns. Furthermore, the outside temperature T.

If the temperature is higher than 11°C, the process moves from step 5T48 to step 5T52, and the outdoor fan (12) is set to high airflow ff1H.
will be set and returned.

In other words, the startup air volume means (
57) outputs an air volume signal, controls the outdoor fan (12), and stops the outdoor fan (12) when the outside air temperature TO is lower than 4°C.
Low air flow is used between 11℃ and high airflow is used when it is higher than 11℃.
H and control the amount of heat exchange.

Thereafter, the operation from step 5T41 is repeated, and thereafter, steps 5T46 and 5T47 are skipped to carry out the above-described operation, and the outdoor fan (12) is set at a predetermined air volume until 30 seconds have elapsed from the time of activation.

When the timer TMI times up after the 30 seconds have elapsed, the process moves from step 5T46 to step 5T53, where the outdoor fan (12) is subjected to normal cooling control and then returned.

Moreover, as shown in F1 to F4 in FIG. 3, compression t! (
Similarly to the control in 1), the outside air temperature TO at the time of shutdown is considered, and the outside air temperature TO is between 4°C and 11°C at the time of shutdown and between 4°C and 13°C at the time of startup (see Fig. 3 F2 to F3). ), it is considered a low wind iL, and the temperature is 4℃ or less when stopped and 6℃ when started.
or less (see Figure 3 F4), it will be stopped, and when stopped
When the temperature is 1° C. or higher, the high wind ff1H may be set as in the flow described above.

As described above, at the start of cooling operation, the outside air temperature T
If o is lower than the predetermined temperature, the capacity of the compressor (1) is unloaded, the outdoor electric expansion valve (5) is fully closed, and the indoor electric expansion valve (7) is opened to a lower degree than the normal superheat degree control opening. In addition, the air volume of the outdoor fan (12) is set to zero or low to ensure a predetermined amount of refrigerant circulation and to maintain the low pressure at a predetermined value.

On the other hand, during heating operation, the four-way selector valve (3) is switched to the broken line in Figure 2, and the refrigerant is transferred from the compressor (1) to the indoor heat exchanger (
8), circulate the outdoor heat exchanger (4) in order. and,
The heating operation of the compressor (1) etc. is controlled (see step ST2 etc.).

Therefore, if the outside temperature is low when starting cooling operation,
In addition to reducing the capacity of the compressor (1), an indoor electric expansion valve (
Since the opening degree of 7) is increased, a predetermined amount of refrigerant circulation can be ensured, and a drop in low pressure can be prevented.

As a result, even if the outside air temperature is low, low pressure cut does not occur, and cooling operation can be started smoothly, so that comfortable cooling can be reliably performed.

Furthermore, when the outside air temperature is low, the outdoor fan (12) is stopped or the air volume is reduced, so that a drop in high pressure can be prevented, and a drop in low pressure accompanying this high pressure drop can be prevented. Therefore, cooling operation can be started more reliably, and comfort can be further improved.

Although this embodiment has been described with reference to a multi-type air conditioner, the present invention is not limited to this, and may also be a cooling-only device.

In addition, the number of capacity stages of the compressor is not limited to two stages, but may be controlled to three or more stages, and the number of control stages of the outdoor fan (12) is not limited to the embodiment, and a medium air volume or the like may be provided. The initial opening AT of the indoor electric expansion valve (7) is not limited to the embodiment, and may be any opening greater than the superheat degree control opening.

FIG. 7 is a control flow showing another embodiment of startup control during cooling operation, and this embodiment is a control flow for a plurality of indoor units, for example, two indoor units (A
), (B). Then, in place of the starting capacity means (55) and starting opening degree means (56) in the previous embodiment, one indoor unit (
A) or (B) starts cooling operation and the indoor heat exchanger (8
) performs heat exchange even if the other indoor unit (B) or (A) has stopped its cooling operation or turned off its thermostat (8).

The controller (50)i is configured with a starting opening means (58) for controlling the opening (8) to be fully closed for a predetermined period of time from the time of starting.

The above startup control operation will be explained based on FIG. 7.

First, when the control operation is started, in step 5T61, the outdoor temperature detected by the outdoor temperature sensor (Th1) is 5°C.
If the outdoor temperature is 5°C or higher, the process moves to step 5T62, and each indoor unit (A),
(B) determines whether the thermostat is on based on the temperature detected by the room thermostat (Th3). During cooling operation when the outdoor temperature is high, each indoor unit (A), (B
) when the thermostat is turned on, the process moves from step 5T62 to step 5T63, where the second opening degree means (53) controls the degree of superheating of the indoor electric expansion valves (7), and returns. Moving to 5T64, the second opening degree means (53) controls the indoor electric expansion valves (7), (7) to fully close, and returns.

This operation is performed during normal cooling operation, and when the cooling operation is stopped, the second opening means (53) opens each indoor unit (A), (
B), each indoor electric expansion valve (7), (7) is controlled to be fully closed.

On the other hand, in step 5T61, the outside temperature is 5°C.
If it is lower, the determination is YES and step 5T6
5, it is determined whether or not the compressor (1) is driving, and if it is, the process moves to step 5T65, where the current
It is determined whether or not the compressor (1) has been started from a stopped state. If the compressor (1) has just been started, the process moves to step 5T67 and a timer is set. In other words, both indoor units (A),
When one or both of (B) is operated for cooling in a low outside temperature state, the compressor (1) is activated and the timer is started.

After that, the process moves from step 5T67 to step 5T68, where it is determined whether or not the timer has timed up.The process moves to step 5T69 until the timer has timed up, controls all the indoor electric expansion valves (7), (7) to be fully closed, and returns. do. Then, step 5T61 and step 5 described above
The operations from T65 to 5T69 will be repeated, and at this time, the determination in step 5T66 will be No since it is not immediately after startup, and the process will skip step 5T67 and proceed to step 5T68, where all the indoor electric expansion valves ( 7), Fully close (7).

In other words, when one of the indoor units (A) and (B) has stopped cooling operation or is in the thermo-off state,
In other words, when the indoor heat exchanger (8) of the indoor unit (A) or (B) does not perform heat exchange, the indoor motorized expansion valve ( 7) is normally controlled to be fully closed, but all indoor motorized valves (7), including the indoor motorized expansion valve (7) of the indoor unit (A) or (B), which starts operating when the outside temperature is low.
.

(7) is fully closed - once.

After that, when the above timer times up, step 5
Moving from T68 to step 5T70, each indoor unit) (
It is determined whether or not A) and (B) are in the thermo-on state, and if the indoor unit (A) or (B) is thermo-on, the process moves to step 5T71 and the indoor electric valve (7) is normally controlled (
If the indoor unit (A) or (B) is thermo-off, step 5T70
Then, the process moves to restep 5T64, and the indoor electric valve (7) is controlled to be fully closed. Further, even in the indoor unit (A) or (B) whose cooling operation is stopped, the indoor electric expansion valve (7) is returned from fully closed to fully closed.

Further, in step 5T65, if the compressor (1) is stopped, the determination becomes No, and step 5T
Moving on to 64, the indoor electric expansion valve (7).

(7) is controlled to be fully closed.

Other configurations and operations are the same as in the previous embodiment.

Therefore, by opening all of the electric expansion valves (7) and (7) in both chambers during start-up when the outside temperature is low, the amount of refrigerant circulation can be reliably maintained at a predetermined value, thereby ensuring that the low pressure does not drop. can be prevented. Especially when the piping length is long, for example, when the distance between the outdoor unit (X) and the indoor units (A), (B) is 100 m, or when only the small capacity indoor unit (A) or CB) is operated. Since a predetermined amount of refrigerant circulation can be reliably secured, low pressure cut can be prevented, and a smooth start of cooling operation can be reliably performed.

In the embodiment shown in FIG. 7, it is not necessary to control the capacity of the compressor (1) at startup as in the previous embodiment. Furthermore, the outdoor fan (12) may be controlled to start up in the same manner as in the previous embodiment.

Furthermore, the opening degree of the indoor electric expansion valve (7) is not limited to fully closed (see step 5T69 in FIG. 7), but may be any degree as long as it can ensure a predetermined amount of refrigerant circulation.

Furthermore, the temperature detection means may use a pressure horn sensor (P1) instead of the outside temperature sensor, and the pressure sensor (P1)
When the evaporation pressure equivalent saturation temperature Te becomes below a predetermined temperature, the indoor electric expansion valve (
7) may be controlled to be fully closed.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are block diagrams showing the configuration of the present invention. Figures 2 to 7 show examples of the present invention, where Figure 2 is a refrigerant system diagram, Figure 3 is a state characteristic diagram of the compressor, indoor electric expansion valve, and outdoor fan relative to outdoor temperature, and Figure 4 is a diagram of the state characteristics of the compressor, indoor electric expansion valve, and outdoor fan.
5 is a control flow diagram of the compressor, FIG. 5 is a control flow diagram of the indoor electric expansion valve, and FIG. 6 is a control flow diagram of the outdoor fan. FIG. 7 is a control flow diagram of an indoor electric expansion valve showing another embodiment. (1) Compressor (4) Outdoor heat exchanger (7) Indoor electric expansion valve (8) Indoor heat exchanger (12) Outdoor fan (Th1) ... Outside temperature sensor (P1) ... Pressure sensor (50) ... Controller (51) ... Capacity control means (53) ... Second opening degree control means (54) ... Air volume control means (55)... Starting capacity means (56), (58)... Starting opening degree means (57)...
Starting air volume means and 2 other people] (b) Fig.

Claims (3)

[Claims] (1) A variable capacity compressor (1) and a heat source side heat exchanger (
4), a user-side expansion valve (7) whose opening degree can be freely adjusted, and a user-side heat exchanger (8) are connected in this order. a capacity control means (51) that adjusts the opening degree of the usage side expansion valve (7) according to the degree of superheating so that the degree of superheating is constant; Temperature detection means (
Th1), and if the outside air temperature drops below a predetermined temperature upon receiving a temperature signal from the temperature detection means (Th1) at the time of startup of the cooling operation, the capacity control means (Th1) is activated within a predetermined time from the time of startup. a starting capacity means (55) for outputting a capacity signal so as to forcibly drive the compressor (1) at a low capacity instead of the control of 53); and a starting capacity means (55) for outputting a capacity signal to forcibly drive the compressor (1) at a low capacity; If the outside air temperature has fallen below a preset temperature in response to a temperature signal, the usage-side expansion valve (7) will be activated within a predetermined period of time from the time of startup, instead of controlling the opening control means (53).
starting opening means (5
6) An operation control device for an air conditioner, comprising: (2) a heat source side heat exchanger (4) equipped with a variable capacity compressor (1), a variable air volume fan (12), and a user side expansion valve (7) whose opening degree can be freely adjusted; User side heat exchanger (8)
and a capacity control means (51) for adjusting the capacity of the compressor (1) according to the air conditioning load; and a capacity control means (51) for adjusting the capacity of the compressor (1) according to the air conditioning load; an opening control means (53) for controlling the degree of superheat to be constant according to
4) and temperature detection means (which detects the outside air temperature and outputs a temperature signal)
Th1), and if the outside air temperature drops below a predetermined temperature upon receiving a temperature signal from the temperature detection means (Th1) at the time of startup of the cooling operation, the capacity control means (Th1) is activated within a predetermined time from the time of startup. a starting capacity means (56) for outputting a capacity signal so as to forcibly drive the compressor (1) at a low capacity instead of the control of 51); and a starting capacity means (56) for outputting a capacity signal to forcibly drive the compressor (1) at a low capacity; If the outside air temperature has fallen below a preset temperature in response to a temperature signal, the usage-side expansion valve (7) will be activated within a predetermined period of time from the time of startup, instead of controlling the opening control means (53).
starting opening means (5
6) When the temperature signal from the temperature detection means (Th1) is received at the time of startup of the cooling operation, and the outside temperature has decreased to a predetermined temperature or less, the air volume control means (Th1) is activated within a predetermined time from the time of startup. 54) A starting air volume means (57) for outputting an air volume signal to forcibly stop or drive the fan (12) at a low air volume. Operation control device. (3) A compressor (1), a heat source side heat exchanger (4), and a plurality of user side expansion valves (7), (7), whose opening degree can be freely adjusted.
・In an air conditioner in which a plurality of user-side heat exchangers (8), (8), ... are connected, each of the above-mentioned user-side expansion valves (7), (7), ... When the heat exchange operation of each user-side heat exchanger (8), (8), ... is stopped, it is controlled to be fully closed, while each user-side heat exchanger (8), (8)
),... during the heat exchange operation, each of the above-mentioned user-side expansion valves (7)
, (7), etc. according to the degree of superheating so that the degree of superheating is constant; A temperature detection means (Th1, P1) outputs a signal, and at least one of the user-side heat exchanger (8) detects the outside air temperature upon receiving the temperature signal from the temperature detection means (Th1, P1) at the time of starting the cooling operation. Or, if the saturation temperature equivalent to evaporation pressure has fallen below a preset temperature, all utilization-side expansion valves (7), instead of controlling the opening degree control means (53), within a predetermined time from startup. (7) An operation control device for an air conditioner, comprising: a starting opening degree means (58) that outputs an opening degree signal so as to set the starting opening degree to a predetermined starting opening degree.